Process for preparing contact mass



June; 17, 1930. 5, JOHN ET AL 1,764,024

PROCESS FOR PREPARING CONTACT MASS Original Filed June 21, 1928 2 Sheets-Sheet 1 lllllillll -&

i 1 g L INVENTORS KENNETH 5. JOHN CARI. W COSLOW I CHRITIAN J. saw/-01- /"I H w ATTORNEY J1me 1930. K. B. JOHN Er AL 1,764,024

PROCESS FOR PREPARING CONTACT MASS Original Filed June 21, 1928 2 Sheets-Sheet 2 I mvz/vroRs KENNETH 5. Jon/v CARL W. Casww CHRISTIAN J- Sanwuvpr BY ATT'aRNEY Patented June 17, 1930 UNITED STATES PATENT OFFICE NENNETH 3. JOHN, OI WILMINGTON, DELAWARE, AND CARL 'W'. COS-LOW AND CHRIS- TIAN J. SGEWINDT, OF PITTSBURGH, PENNSYLVANIA, ASSIGNORS TO THE SELDEN COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF DELAWARE PROCESS FOR PREPARING CONTACT MASS original a lication glednme a1, 1928, Serial 166. 287,170. Divided 14, 1929. Serial No. 339,899.-

This invention relates to a process of formg contact mass pellets from moistened pulverulent material.

Contact mass for many reactions such as for example, the contact sulfuric acid process, the oxidation of certain organic compounds, etc. is made by compacting material which consists of more or less finely divided aggregates such as kieselguhr moistened with iocatalytically active binders. The examples of such catalysts compositions may be found in the patents to Alphons O. J aeger, No. 1,694,123 dated December 4, 1928; No. 1,675,308 dated June 26, 1928; No. 1,675,309 dated June 26, 1928; No. 1,685,635 dated Sept. 25, 1928; No. 1,692,126 dated Nov. 20, 1928; and patent to J aeger and Bertsch, No. 1,657,754 dated January 31, 1928. The particular catalytic compositions do not form any 80 part of the present invention which is directed to a method of forming pellets from any catal st compositions having similar physical c aracteristics.

he formation pellets from catalyst compositions consisting of finely divided material moistened with binders usually requires pressing the material into plates or dies with accurate perforations which perforations are filled with the adherent powdered material 30 which is then ressed to compact it and cause it to assume t e form of the perforation in the die. In order to produce the best results, it is necessary to exert considerable pressure equally from both sides and rollers such pressure on the material in the plate which rollers must be capable of swinging apart as the plates pass throu h them. At the same time it is desirable t at the drive of the rollers be very uniform and positive even though the rollers may be separated by quite a distance. In the preferred embodiment of the present invention, therefore, flexible drives such as belts or chains are not used for the rollers which are driven by a anon-flexible drive such as a gear train or friction wheels. Where it is desired to effect large production with a minimum of labor it is also desirable to use an automatic feeding mechanism for the platesthough the are used in the present invention to exert and this application. filed February invention is not limited to a process in which the plates are fed automatically.

In general in carrying out the process of the present invention plates having suitable perforations are passed down through a hopa per containing the moist catalytic material. The feed of the plates may either be automatic or manual. The bottomof the hopper opens on the rolls and as the plates pass through, the material in the perforations is compacted by the rolls which are so arranged that they can move apart without disengagw ing the gears. Preferably this is effected by providing the rollers with gears meshing with other gears on parallel shafts, the rollers being journaled in frames which are capable of rocking about an axis coinciding -with the axes of the drive shafts so that no matter how far the rolls swing apart the distance from the roll axis to the center of the drive shaft remains constant. and thereforethe driving and driven gears remain continuously in mesh on a pitch circle of unvarying diameter.

The invention will be described in greater detail in connection with the manufacture of diluted zeolite contact masses in which kieselguhr moistened with a zeolite gel is formed into cylindrical pellets. The figures of the drawings show a machine in which the process can be carried out.

Fig. 1 is a vertical section through a tablet machine embodying the features of the present invention;

Fig. 2 is a plan view of a plate;

Fig. 3 is a vertical section taken at right angles to Fig. 1 along the line 3-3; and

Fig. 4 is a vertical section at right angles to Fig. 1 taken along the line 44.

The machine consists essentially in a ho per 1, and compacting rolls 2 which may e smooth or ribbed. The rolls are mounted on shafts 3, passing through frames 4, which powdered material. It is vitally essential with diluted zeolite contact masses that the rolls be scraped clean of adherent material as otherwise they will not properly compact the material over the plate surface, thus producing pellets of unsatisfactory physical structure and surface. Each roll shaft carries a-gear 10, the gears for both rolls being on either the same end or opposite'ends, the latter case being shown in Fig. 1. The gears are in turn driven by pinions 11, meshing therewith, which pinions are keyed to shafts 12 coaxial with the pins 5. These shafts 12 are suitably journaled in mountings 13 on the main frame and may be driven through gears 14 or by any other suitable means. For simplicitys sake, the gears on the ends of the rolls are shown on opposite ends of the roll shafts and two gears 14 are shown. In practice it is generally simpler to use a single driving source and have gears 10 on the same side of the machine. The principle of operation, of course, is identical.

In operation the hopper is filled with zeolite-kieselguhr powder and plates '15 ass down through the plate magazine (see igs. 1 and 4) passing from'the plate magazine through the powdered material at the bottom of the hopper and then between the rolls 2. The powder which fills the perforations 17 in the plates 15 to overflowing is compressed into the perforations by the rollers, thus forming firm pellets in the plate. Any surplus powder is scraped from the rollers by the scrapers 9 (see Fig. 4). The plates after passing through the rollers can then be placed by hand on a plate with suitable projections reglstering with the perforations'in order to press out the pellets formed.

' This may be done by hand, but is pre eifected by suitable scraping means incor- It will be apparent that the machine operates simply and reliably, the rollers 2 always being in tight contact either with special separators or with the plates as they pass through and the machlne operates uninterruptedly with plates of any thickness. The plate feeding magazine permits more rapid operation ,as the plates are fed by gravity when in the correct position but where large production is not essential the magazine may be dispensed with and the plates may be placed in the hopper by hand. It is usually necessa to agitate the powder in order to keep it in contact with t e emergin plates and to revent any tendency to orming lumps. is may be done manually oran suitable jarring means may be .employe such as for example a tapper which continuously taps the side of the hopper 1. These devices are of well known type and are not shown in the drawings.

It is desirable to cleanthe plates of adherent material before removing the pellets. erably porated in the tablet machine. In the drawing these means are shown diagrammatically as two spring pressed knives 18 (see Figs. 1 and 4). The-knives are provided with inclined cutting edges, and each knife possesses a lip 19, bent back so that the plate striking the lip 19 forces the knives apart sufficiently to permit it to pass therethrough. The sharp knife edges clean off superfluous material and the pellets can then be discharged as described above. Any other suitpellets. a

While it is a peculiar advantage of the present invention that it is possible to drive the machine entirely positively through gears without encountering any difliculties in meshing with different roll separations, it should be understood that the machine can also be operated with flexible driving means, such as chainsand belts, in which-case the fact that the axes of the roll shafts swing about an axis coincident with that of the driving shaft keeps a uniform tension on the flexible driving means, a very great advantage although not as essential as in the case of gears for it is of course possible to operate machines in which the axes do not move in circles around the drive shaft when flexible driving means are used but, of course, a much less eflective drive is obtained. The advantages of the present invention, therefore, are very marked even-with highly flexible drives. :2

This application is a division of our copending application Serial No. 287 ,170, filed June 21, 1928, now Patent 1,741,312, December 31, 1929.

What is claimed as new is:

1. A process of forming catalyst pellets, which comprises introducing a compactible pulverulent catalyst material into the perforations extending entirely through a plate or die, passing theplate between compacting or die, passing the plates between compacting means acting from both sidesfimd exerting substantially uniform pressure on both sides of the plate, uniformly driving forward the plate irrespective of variations in; the-thickness thereof, removing adherent material 1 from the surfaces of the plate and pressing out pellets therefrom.

Signed at Carneys Pt., N. J., this 24th day of January, 1929.

KENNETH B. JOHN. Signed atPittSburgh, Pennsylvania, this 11th day of February, 1929.

CARL W. COSLOW. CHRISTIAN J. SCHWINDT. 

